Conventionally, there has been known a crane equipped with a machine body, a boom that is mounted to the machine body in a raisable and lowerable manner, and a raisable and lowerable member that can be raised and lowered with respect to the boom.
Such a crane may sometimes be assembled in a workplace where a work for suspending a load is performed. Specifically, the raisable and lowerable member and the boom which are laid down are raised. Thus, the crane becomes ready to suspend a load.
For example, Japanese Unexamined Patent Publication No. 2010-538930 discloses a method for raising a strut of a crane, the strut being mounted to a boom in a raisable and lowerable manner With this method, the strut is laid down, and with this state, a supporting post extending upward from the upper surface of the strut is attached to the strut. Next, a rope is connected to the supporting post. Then, the rope is wound up to the boom side, whereby the strut is raised.
However, with the method disclosed in Japanese Unexamined Patent Publication No. 2010-538930, that is, the method for raising the strut (raisable and lowerable member) by winding up the rope connected to the strut (raisable and lowerable member), if the raising amount of the raisable and lowerable member is small, the rope passes close to the upper surface of the boom. Therefore, an interference between the rope and the upper surface of the boom or various members mounted on the upper surface occurs, which is likely to damage the rope.